Method for suppressing gelation of metalworking fluids and method for manufacturing metalworking fluids

Abstract

To provide a metalworking oil agent gelling inhibition method which can well inhibit a metalworking oil agent from gelling.SOLUTION: A metalworking oil agent gelling inhibition method includes a step of mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and an oil agent including a saturated hydrocarbon compound, where the content of the water is 5.0 wt.% or more and 7.0 wt.% or less.SELECTED DRAWING: None

Description

Technical Field

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[0001] The present invention relates to a method for suppressing gelation of a metalworking fluid and a method for producing a metalworking fluid.

Background Art

[0002] In the field of metalworking such as cutting and grinding, metalworking fluids are used for lubrication. Metalworking fluids include oil-based and water-soluble metalworking fluids. Water-soluble metalworking fluids are widely used because they have excellent cooling and wetting properties and no fire hazard. During metalworking, a large amount of metalworking fluid is circulated by a pump and used.

[0003] For example, Patent Document 1 discloses a water-soluble metalworking fluid containing 2-phenoxyethanol.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is a problem that metalworking fluids may gel at low temperatures. Gelation of metalworking fluids causes clogging and thickening in the equipment where the metalworking fluids are used, leading to a decrease in mechanical efficiency.

[0006] The main object of the present disclosure is to provide a method for suppressing gelation of a metalworking fluid and the like that can effectively suppress gelation of the metalworking fluid.

Means for Solving the Problems

[0007] Aspects of the present disclosure for solving the above problems are as follows.

[0008] (1) A method for suppressing gelation of a metalworking fluid according to one aspect of the present disclosure includes a step of mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and a fluid containing a saturated hydrocarbon compound, wherein the water content is 5.0% by weight or more and 7.0% by weight or less.

[0009] (2) In the method for suppressing gelation of metalworking fluid described in (1) above, the content of the unsaturated hydrocarbon compound may be 0.4% by weight or more.

[0010] (3) In the method for suppressing gelation of metalworking fluids described in (1) or (2) above, the weight ratio of water to the unsaturated hydrocarbon compound (water / unsaturated hydrocarbon compound) may be 0.2 or more and 12.0 or less.

[0011] (4) In the method for suppressing gelation of a metalworking fluid described in any one of (1) to (3) above, the unsaturated hydrocarbon compound may be one or more selected from oleic acid, castor oil condensed fatty acid, sorbitan monooleate, oleyl alcohol, polyoxyethylene alkyl ether, and polyoxyalkylene oleyl cetyl ether.

[0012] (5) In the method for suppressing the gelation of a metalworking fluid described in any one of (1) to (4) above, the saturated hydrocarbon compound may be a paraffinic mineral oil.

[0013] (6) In the method for suppressing gelation of a metalworking fluid described in any one of (1) to (5) above, the metalworking fluid may be used at a temperature of 5°C or lower.

[0014] (7) A method for producing a metalworking fluid according to one aspect of the present disclosure includes the step of mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and a fluid containing a saturated hydrocarbon compound, The water content is 5.0% by weight or more and 7.0% by weight or less. [Effects of the Invention]

[0015] This disclosure provides a method for suppressing the gelation of metalworking fluids, which can effectively suppress the gelation of metalworking fluids. [Brief explanation of the drawing]

[0016] [Figure 1] This image is used to explain the evaluation criteria for the undiluted solution. [Modes for carrying out the invention]

[0017] Preferred embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. The elements listed below can be combined in any way, and the scope of the present invention is intended to include all modifications within the claims and equivalents thereof. Furthermore, the upper and lower limits exemplified in this specification for numerical ranges can be arbitrarily combined to create new numerical ranges.

[0018] (Method for suppressing gelation of metalworking fluids) The method for suppressing gelation of a metalworking fluid according to this embodiment (hereinafter also simply referred to as the gelation suppression method) is a method for suppressing gelation of a metalworking fluid, comprising the step of mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and an oil containing a saturated hydrocarbon compound, characterized in that the water content is 5.0% by weight or more and 7.0% by weight or less. In this specification, gelation refers to a state in which a fluid metalworking fluid loses its fluidity (a state in which it shows almost no fluidity or no fluidity at all).

[0019] Conventional metalworking fluids, even if fluid at room temperature, sometimes gel at low temperatures. The metalworking fluid to which the gelation suppression method of the embodiment is applied exhibits excellent low-temperature fluidity and can demonstrate superior gelation suppression at low temperatures compared to conventional metalworking fluids. When using or storing a metalworking fluid to which the gelation suppression method of the embodiment is applied, the temperature is preferably room temperature (for example, about 15°C or higher and 30°C or lower), but it can be used or stored without gelation even in a low-temperature environment (for example, about -10°C or higher and 5°C or lower, more specifically, about -10°C or higher and 3°C or lower, even more specifically, about -10°C or higher and 0°C or lower).

[0020] In the gelation suppression method of the present embodiment, for an oil agent containing a saturated hydrocarbon compound, gelation of the metalworking fluid is suppressed by blending an unsaturated hydrocarbon compound having an HLB of 8.0 or less and water within a predetermined range.

[0021] In this specification, HLB is an abbreviation for Hydrophile - lipophile balance (hydrophilic - lipophilic balance), and is an index indicating the balance between hydrophilic and lipophilic groups in the molecule of a compound. In this specification, HLB is a value defined by the following calculation formula by the Griffin method. HLB value = 20 × [sum of chemical formula weights of hydrophilic parts] / molecular weight

[0022] The gelation suppression method includes a step of mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and an oil agent containing a saturated hydrocarbon compound. As the mixing method, although not particularly limited, for example, a known method such as stirring can be used. Also, the order of addition of each component is not particularly limited.

[0023] Hereinafter, each component of the metalworking fluid to which the gelation suppression method of the present embodiment is applied will be described. The metalworking fluid contains an unsaturated hydrocarbon compound having an HLB of 8.0 or less, water, and an oil agent containing a saturated hydrocarbon compound.

[0024] [Unsaturated Hydrocarbon Compound] In the gelation suppression method of the present embodiment, as described above, gelation of the metalworking fluid is suppressed by blending an unsaturated hydrocarbon compound. The unsaturated hydrocarbon compound used in the gelation suppression method of the embodiment is a compound having an unsaturated hydrocarbon chain in the molecule.

[0025] The unsaturated hydrocarbon compound has an HLB of 8.0 or less. When the HLB of the unsaturated hydrocarbon compound is 8.0 or less, the overall HLB of the metalworking fluid can be maintained well, improving the stability of the metalworking fluid. Therefore, it is possible to suppress problems such as stratification of the metalworking fluid while exhibiting excellent gelation suppression. From the viewpoint of gelation suppression, the HLB of the unsaturated hydrocarbon compound is more preferably between 0.5 and 4.5, and even more preferably between 1.0 and 4.5.

[0026] Examples of unsaturated hydrocarbon compounds include oleic acid, castor oil condensed fatty acids, sorbitan monooleate, oleyl alcohol, polyoxyethylene alkyl ethers, and polyoxyalkylene oleyl cetyl ethers. Unsaturated hydrocarbon compounds may be used alone or in combination of two or more. From the viewpoint of inhibiting gelation, oleic acid, castor oil condensed fatty acids, sorbitan monooleate, and oleyl alcohol are preferred among the unsaturated hydrocarbon compounds, with oleic acid, sorbitan monooleate, and oleyl alcohol being more preferred.

[0027] Examples of commercially available unsaturated hydrocarbon compounds with an HLB of 8.0 or less include NAA-35 (manufactured by NOF Corporation), MINERASOL PCF-45 (manufactured by Ito Oil Co., Ltd.), Nonion OP-80R (manufactured by NOF Corporation), Angecol 90N (manufactured by Shin Nippon Rika Co., Ltd.), Pelletex 2917H, Pelletex 2918H (both manufactured by Miyoshi Oil & Fat Co., Ltd.), and Neugen ET-89 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0028] From the viewpoint of gelation suppression, the above-mentioned unsaturated hydrocarbon compounds preferably have 12 to 80 carbon atoms in the lipophilic group, more preferably 14 to 76 carbon atoms, even more preferably 16 to 72 carbon atoms, and most preferably 16 to 20 carbon atoms.

[0029] In the gelation suppression method of the embodiment, the content of the unsaturated hydrocarbon compound is preferably 0.4% by weight or more, more preferably 0.5% by weight or more, even more preferably 0.9% by weight or more, and most preferably 1.0% by weight or more, in the metalworking fluid from the viewpoint of gelation suppression, and preferably 16% by weight or less from the viewpoint of obtaining gelation suppression and an effect commensurate with use, and any combination of these ranges may be used. When two or more types are used in combination, the content refers to the total amount.

[0030] From the viewpoint of inhibiting gelation, the content of unsaturated hydrocarbon compounds in the metalworking fluid is preferably 0.4% to 16% by weight when the HLB of the unsaturated hydrocarbon compounds is less than 4.5 or between 0.5 and 4.5, preferably 0.4% to 7.5% by weight when the HLB is between 4.5 and 7.0, and preferably 0.4% to 3.5% by weight when the HLB is between 7.0 and 8.0.

[0031] [water] In the gelation suppression method of this embodiment, as described above, gelation of the metalworking fluid is suppressed by incorporating water within a predetermined content range. The water used in the gelation suppression method of this embodiment may be tap water, industrial water, ion-exchanged water, distilled water, etc., and it does not matter whether the water is hard water or soft water. Water may be used alone or in combination of two or more types.

[0032] The metalworking fluid may be in either emulsion or soluble form, but it is preferably in emulsion form.

[0033] In the gelation suppression method of the embodiment, the water content in the metalworking fluid is 5.0% by weight or more and 7.0% by weight or less. When the water content is within the above range, layering of the metalworking fluid can be suppressed, and gelation of the metalworking fluid can be significantly suppressed. From the viewpoint of gelation suppression, the water content in the metalworking fluid is preferably 5.3% by weight or more, more preferably 6.0% by weight or more, and even more preferably 6.3% by weight or more, and from the viewpoint of layering suppression, 6.7% by weight or less is preferred. When two or more types are used in combination, the content refers to the total amount.

[0034] The water content is preferably 5.0 parts by weight or more and 7.0 parts by weight or less, more preferably 5.4 parts by weight or more and 7.0 parts by weight or less, even more preferably 6.0 parts by weight or more and 7.0 parts by weight or less, and most preferably 6.4 parts by weight or more and 7.0 parts by weight or less, based on 100 parts by weight of the total of water and the oily components described later.

[0035] The weight ratio of water to the unsaturated hydrocarbon compound (water / unsaturated hydrocarbon compound) is preferably 0.2 to 12.0, and more preferably 2.6 to 12.0, from the viewpoint of synergistic effect and gelation suppression. The weight ratio of water to the unsaturated hydrocarbon compound is preferably 0.2 to 12.0 when the HLB of the unsaturated hydrocarbon compound is less than 4.5 or 0.5 to less than 4.5, preferably 0.7 to 12.0 when the HLB is 4.5 to less than 7.0, and preferably 1.5 to 12.0 when the HLB is 7.0 to 8.0.

[0036] [Oils] The oil formulation contains a base oil as a saturated hydrocarbon compound. The base oil is not particularly limited as long as it contains saturated hydrocarbons, and examples include mineral oil and synthetic oil. Examples of mineral oil include paraffinic mineral oil and naphthenic mineral oil. Examples of synthetic oil include hydrocarbon-based synthetic oil. oil etc.Examples include synthetic oils. Among these, mineral oil is preferred as the base oil, and paraffinic mineral oil is more preferred. When the present method is applied to a metalworking fluid containing paraffinic mineral oil, which easily gels at low temperatures, its effect is remarkably evident. The base oil may be used alone or in combination of two or more types.

[0037] The base oil content is preferably 40 parts by weight or more, more preferably 45 parts by weight or more, and even more preferably 50 parts by weight or more, per 100 parts by weight of the total of the oil components and water, from the viewpoint of processability. Furthermore, from the viewpoint of inhibiting gelation and stability of the metalworking oil, it is preferably 80 parts by weight or less, more preferably 75 parts by weight or less, and even more preferably 70 parts by weight or less. Any combination of these ranges is acceptable. When two or more types are used in combination, the content refers to the total amount.

[0038] The oil used in the gelation suppression method of the embodiment may contain, in addition to the base oil components described above, fatty acids, various additives, etc., as necessary, within a range that does not hinder the effects of the present invention. Examples of additives include amines, surfactants, rust inhibitors, fungicides, corrosion inhibitors, and antibacterial agents.

[0039] Examples of fatty acids include monocarboxylic acids and dicarboxylic acids. Examples of monocarboxylic acids include pelargonic acid, lauric acid, stearic acid, and coconut oil fatty acids as natural products. Examples of dicarboxylic acids include adipic acid, sebacic acid, undecanediic acid, and dodecanediic acid. Fatty acids may be used individually or in combination of two or more types.

[0040] The fatty acid content can be, for example, 0.5 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the total of the oil components and water, from the viewpoint of processability. When two or more types are used in combination, the content refers to the total amount.

[0041] Examples of amines include organic amines such as alkanolamines. Examples of organic amines include primary alkanolamines (e.g., monoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol), secondary alkanolamines (e.g., N-methylethanolamine, diethanolamine, diisopropanolamine, etc.), and tertiary alkanolamines (e.g., N-methyldiethanolamine, N-cyclohexyldiethanolamine, triethanolamine, triisopropanolamine, etc.). Amines may be used individually or in combination of two or more types.

[0042] The amine content can be, for example, 1.0 part by weight or more and 10.0 parts by weight or less per 100 parts by weight of the total oil component and water, from the viewpoint of emulsification stability. When two or more amines are used in combination, the content refers to the total amount.

[0043] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Surfactants may be used alone or in combination of two or more types. Among the surfactants, nonionic surfactants and anionic surfactants are preferred, and a combination of nonionic and anionic surfactants is more preferred.

[0044] Examples of nonionic surfactants include ethers such as polyoxyethylene alkylphenyl ethers and polyoxyethylene polyoxypropylene glycol, esters such as sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters and polyoxyethylene fatty acid esters, and amides such as fatty acid alkanolamides. Examples of anionic surfactants include polyoxyethylene alkyl ether carboxylic acid, polyoxyethylene alkyl ether phosphate, alkylbenzene sulfonic acid, α-olefin sulfonic acid, and salts thereof. Examples of cationic surfactants include quaternary ammonium salts such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, and alkyldimethylbenzylammonium salt. Examples of amphoteric surfactants include alkylbetaine as a betaine-based surfactant.

[0045] The surfactant content can be, for example, 10.0 parts by weight or more and 30.0 parts by weight or less per 100 parts by weight of the total oil component and water, from the viewpoint of emulsification stability. When two or more types are used in combination, the content refers to the total amount. When nonionic surfactants and anionic surfactants are used in combination, the content of the nonionic surfactant can be, for example, 5.0 parts by weight or more and 15.0 parts by weight or less per 100 parts by weight of the total oil component and water, and the content of the anionic surfactant can be, for example, 5.0 parts by weight or more and 15.0 parts by weight or less per 100 parts by weight of the total oil component and water.

[0046] Examples of rust inhibitors include dibasic acids and organic amines. Rust inhibitors may be used alone or in combination of two or more. The amount of rust inhibitor can be, for example, 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the total amount of oil components and water, from the viewpoint of rust prevention. When two or more types are used in combination, the amount refers to the total amount.

[0047] Examples of antifungal agents include organic amines. Antifungal agents may be used alone or in combination of two or more. The amount of antifungal agent can be, for example, 1.0 part by weight or more and 7.0 parts by weight or less per 100 parts by weight of the total amount of oil components and water, from the viewpoint of antifungal activity. When two or more types are used in combination, the amount refers to the total amount.

[0048] Examples of corrosion inhibitors include benzotriazole, chromate, metasilicate, and phosphate. Corrosion inhibitors may be used alone or in combination of two or more. The content of the corrosion inhibitor can be, for example, 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the total oil component and water, from the viewpoint of corrosion inhibition. When two or more are used in combination, the content refers to the total amount.

[0049] Examples of antibacterial agents include benzimidazole-based antibacterial agents, benzothiazoline-based antibacterial agents, thiadiazole-based antibacterial agents, and pyridine-based antibacterial agents. Antibacterial agents may be used alone or in combination of two or more. The amount of antibacterial agent can be, for example, 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the total amount of oil components and water, from the viewpoint of antibacterial activity. When two or more types are used in combination, the amount refers to the total amount.

[0050] The metalworking fluid used in the gelation suppression method of the embodiment may contain an unsaturated hydrocarbon compound as an oil component, as long as it satisfies the condition that it contains an unsaturated hydrocarbon compound with an HLB of 8.0 or less, water within a predetermined content range, and an oil containing a saturated hydrocarbon compound. However, from the viewpoint of enhancing the effects of the present invention, it is preferable that the content of the unsaturated hydrocarbon compound as an oil component is small, more preferably that it substantially does not contain an unsaturated hydrocarbon compound as an oil component, and even more preferably that it does not contain an unsaturated hydrocarbon compound as an oil component.

[0051] If the oil formulation is substantially free of unsaturated hydrocarbon compounds, the content of the unsaturated hydrocarbon compounds is preferably 1 part by weight or less, more preferably 0.1 parts by weight or less, per 100 parts by weight of the total amount of the oil formulation.

[0052] Furthermore, when metalworking fluids contain unsaturated hydrocarbon compounds as oil components, these unsaturated hydrocarbon compounds are distinguished from the unsaturated hydrocarbon compounds added to eliminate gelation as described above. In other words, the regulations regarding the content and content ratio of unsaturated hydrocarbon compounds added to eliminate gelation as described above do not include unsaturated hydrocarbon compounds as oil components.

[0053] (Method of manufacturing metalworking fluid) The metalworking fluid of the embodiment is obtained by mixing and stirring the above components. The order in which the components are added is not particularly limited.

[0054] The metalworking fluid described above may also be used as a metalworking solution, which is prepared by diluting the metalworking fluid with water. The metalworking solution (diluted solution) can be used as a coolant for metalworking.

[0055] Metalworking fluids are obtained by diluting metalworking oils with water. Any type of water can be used, such as tap water, industrial water, deionized water, or distilled water, and it does not matter whether the water is hard or soft.

[0056] The dilution ratio when diluting metalworking fluid with water can be appropriately adjusted according to the composition of the metalworking fluid and the performance required during metalworking. The dilution ratio is not limited, but it is generally preferable to dilute it to 1.5 times or more and 100 times or less. From the viewpoint of further enhancing the effects of the present invention and improving processing characteristics, it is more preferable to dilute it to 5 times or more, even more preferably to 10 times or more, and more preferably to 50 times or less, and even more preferably to 30 times or less.

[0057] Metalworking fluids (undiluted) and metalworking liquids (diluted) have excellent gelation suppression and workability, making them suitable for metalworking, such as cutting, grinding, polishing, and slicing. Examples of metals to be processed include ferrous metals and their alloys, non-ferrous metals such as aluminum, magnesium, and copper, and their alloys. [Examples]

[0058] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not intended to be limited to those examples. Parts and percentages in the examples are by weight unless otherwise specified.

[0059] (Preparation of metalworking fluids) [Example 1] To 100.0 g of Blank 1, which was prepared by blending each component of (A) oil and 5.5% by weight of (B) water as shown in Table 1 below, 2.0 g of oleic acid as component (C) was added and mixed in a stirrer until homogeneous to obtain the metalworking oil of Example 1. The composition of the metalworking oil is shown in Tables 2 to 6 below. In Tables 2 to 6, the values ​​of water shown in parentheses represent the amount of (B) water relative to the total amount of (A) oil and (B) water, i.e., the water content (by weight) in the blank. The weight ratio of (B) water to component (C) ((B) water / component (C)) is also indicated.

[0060] [Example 2] (B) The metalworking fluid for Example 2 was prepared in the same manner as in Example 1, except that Blank 2 was used, in which the water content ratio was 6.5% by weight.

[0061] [Comparative Example 1] (B) A metalworking fluid for Comparative Example 1 was prepared in the same manner as in Example 1, except that Blank 3 was used, in which the water content ratio was 4.5% by weight.

[0062] [Examples 3-14, Comparative Examples 2-37] The metalworking fluids for Examples 3-14 and Comparative Examples 2-37 were prepared in the same manner as in Example 1, except that Blank 1 was used when the water content in parentheses was 5.5% by weight, Blank 2 was used when it was 6.5% by weight, and Blank 3 was used when it was 4.5% by weight.

[0063] [Table 1]

[0064] [Table 2]

[0065] [Table 3]

[0066] [Table 4]

[0067] [Table 5]

[0068] [Table 6]

[0069] In Blanks 1 to 3 shown in Table 1 above, the same (A) oil was used, and each blank was prepared by varying only the amount of (B) water mixed with the (A) oil.

[0070] The details of component (C) used in Tables 2-6 above are as follows: (C1) Oleic acid: NAA-35 (manufactured by NOF Corporation), HLB 3.2, contains unsaturated hydrocarbon chain, lipophilic group has 17 carbon atoms. (C2) Castor oil condensed fatty acid: MINERASOL PCF-45 (manufactured by Ito Oil Co., Ltd.), HLB 0.8, contains unsaturated hydrocarbon chain, lipophilic group has 71 carbon atoms. (C3) Sorbitan monooleate: Nonionic OP-80R (manufactured by NOF Corporation), HLB 4.3, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C4) Oleyl alcohol: Angecol 90N (manufactured by Shin Nippon Rika Co., Ltd.), HLB 1.3, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C5) Polyoxyethylene alkyl ether: Pelletex 2917H (manufactured by Miyoshi Oil & Fat Co., Ltd.), HLB 4.8, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C6) Polyoxyethylene alkyl ether: Pelletex 2918H (manufactured by Miyoshi Oil & Fat Co., Ltd.), HLB 6.4, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C7) Polyoxyalkylene oleyl cetyl ether: Neugen ET-89 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), HLB 7.9, contains unsaturated hydrocarbon chain, lipophilic group has 16 or 18 carbon atoms. (C8)2-Phenoxyethanol, HLB 2.5, no unsaturated hydrocarbon chain. (C9)Na sulfonate:Sulfole 465 (manufactured by MORESCO Corporation), HLB 3.6, no unsaturated hydrocarbon chain, 28 carbon atoms in the lipophilic group. (C10) Polyoxyalkylene lauryl ether: DKS NL-DASH403 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), HLB 6.5, no unsaturated hydrocarbon chain, 12 carbon atoms in the lipophilic group. (C11) Hydrogenated beef tallow fatty acid: STEARIC ACID (POFAC1660L) (manufactured by SOUTHERN ACIDS INDUSTRIES SDN. BHD), HLB 3.2, no unsaturated hydrocarbon chain, 17 carbon atoms in the lipophilic group. (C12) Stearyl alcohol: Conol 30S (manufactured by Shin Nippon Rika Co., Ltd.), HLB 1.3, no unsaturated hydrocarbon chain, 18 carbon atoms in the lipophilic group. (C13) Polyoxyethylene oleyl ether: Emulgen 404 (manufactured by Kao Corporation), HLB 8.8, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C14) Polyoxyethylene oleyl ether: Emulgen 408 (manufactured by Kao Corporation), HLB 10.0, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C15) Polyoxyethylene oleyl ether: Emulgen 420 (manufactured by Kao Corporation), HLB 13.6, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms. (C16) Polyoxyethylene oleyl ether: Emulgen 430 (manufactured by Kao Corporation), HLB 16.2, contains unsaturated hydrocarbon chain, lipophilic group has 18 carbon atoms.

[0071] (Evaluation of gelation inhibition) Each metalworking fluid (undiluted) was left to stand at 0°C for one day. After standing, the appearance of the undiluted fluid was visually inspected and evaluated according to the following criteria. In cases A and B, good gelation inhibition was determined. The evaluation results are shown in Tables 7 and 8. (Evaluation Criteria) A: The gelation has been resolved. B: Gelation is resolved, but the viscosity is still somewhat high. C: Gelation is occurring. D: Solidification is occurring. E: Separation has occurred. Furthermore, the stock solutions of each example and comparative example all exhibited fluidity at room temperature, without gelation, solidification, or layering.

[0072] Figure 1 is an image illustrating the evaluation criteria for the undiluted solution. Figure 1 is an illustrative image illustrating the evaluation criteria and does not limit the actual evaluation results.

[0073] [Table 7]

[0074] [Table 8]

[0075] Tables 7 and 8 show that the metalworking fluids of Examples 1 to 14, which were formulated with 5.0% to 7.0% by weight of water, an unsaturated hydrocarbon compound with an HLB of 8.0 or less, and an oil containing a saturated hydrocarbon compound, showed good gelation resolution. In contrast, the metalworking fluids of Comparative Examples 1 to 7, which did not contain water within the above content range, and Comparative Examples 8 to 37, which did not contain an unsaturated hydrocarbon compound with an HLB of 8.0 or less, did not show sufficient gelation resolution.

[0076] In the comparative examples using Blank 3, which had a water content of 4.5% by weight, all metalworking fluids solidified at low temperatures and did not exhibit gelation-inhibiting properties. In contrast, the metalworking fluids in each example containing a predetermined range of water showed no gelation, confirming that the liquid state is improved by adding an appropriate amount of water. Examples 3, 4, 9-14 and Comparative Examples 2, 5-7, etc., confirmed that increasing the amount of water contributes to improved gelation-inhibiting properties.

[0077] Comparative Examples 8-19 confirmed that when compounds containing saturated hydrocarbon chains were used, the gelation resolution effect was insufficient, resulting in poor gelation suppression (gelation resolution). Comparative Examples 20-25 confirmed that when compounds without unsaturated hydrocarbon chains and with an HLB of 8.0 or less (small hydrophilic portion) were used, not only was gelation not resolved, but the liquid solidified. Comparative Examples 26-37 confirmed that when unsaturated hydrocarbon compounds with an HLB greater than 8.0 were used, the gelation resolution effect was insufficient, resulting in poor gelation suppression (gelation resolution).

[0078] Next, we investigated the gelation-inhibiting effect when the content of component (C) was changed.

[0079] [Examples 15-63, Comparative Examples 38-45] Examples 15-63 and Comparative Examples 38-45 were prepared in the same manner as Example 1, except that Blank 1 (5.5% by weight of water) shown in Table 1 was used as the base formulation, and the mixing ratios of each component were as shown in Tables 9-16.

[0080] For Examples 15-63 and Comparative Examples 38-45, the gelation inhibition was evaluated using the same method as described above for each of the Examples and Comparative Examples. The evaluation results are shown in Tables 9-16. Note that the stock solutions of each Example and Comparative Example all exhibited fluidity at room temperature, without gelation, solidification, or stratification.

[0081] [Table 9]

[0082] [Table 10]

[0083] [Table 11]

[0084] [Table 12]

[0085] [Table 13]

[0086] [Table 14]

[0087] [Table 15]

[0088] [Table 16]

[0089] Tables 9-16 show that the metalworking fluids of Examples 15-63, which contained unsaturated hydrocarbon compounds with an HLB of 8.0 or less, exhibited excellent gelation inhibition. Examples 15-46 showed that in the case of unsaturated hydrocarbon compounds with relatively low HLB, excellent gelation inhibition was obtained at relatively high concentrations. In contrast, Examples 47-63 showed that in the case of unsaturated hydrocarbon compounds with relatively high HLB, no improvement in gelation inhibition was observed with increasing content.

[0090] Based on the above, it has been confirmed that the metalworking fluid using the gelation suppression method of this disclosure effectively suppresses gelation.

Claims

1. The process includes mixing water, an unsaturated hydrocarbon compound having an HLB of 8.0 or less, and an oil containing a saturated hydrocarbon compound. The water content is 5.0% by weight or more and 7.0% by weight or less. The weight ratio of water to the unsaturated hydrocarbon compound (water / unsaturated hydrocarbon compound) is 0.2 or more and 12.0 or less. A method for suppressing gelation of metalworking fluids.

2. The content of the aforementioned unsaturated hydrocarbon compound is 0.4% by weight or more. A method for suppressing gelation of a metalworking fluid according to claim 1.

3. The unsaturated hydrocarbon compound is one or more selected from oleic acid, castor oil condensed fatty acid, sorbitan monooleate, oleyl alcohol, polyoxyethylene alkyl ether, and polyoxyalkylene oleyl cetyl ether. A method for suppressing gelation of a metalworking fluid according to claim 1 or claim 2.

4. The saturated hydrocarbon compound is a paraffinic mineral oil. A method for suppressing gelation of a metalworking fluid according to claim 1 or claim 2.

5. The aforementioned metalworking fluid is used at temperatures below 5°C. A method for suppressing gelation of a metalworking fluid according to claim 1 or claim 2.

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